Aromatic L-amino acid decarboxylase inhibitor

Aromatic L-amino acid decarboxylase inhibitor

An aromatic L-amino acid decarboxylase inhibitor (AAAD inhibitor) is a type of enzyme inhibitor that specifically targets the enzyme aromatic L-amino acid decarboxylase (AADC). This enzyme is crucial in the biosynthesis of several important neurotransmitters, including dopamine, serotonin, and norepinephrine. By inhibiting AADC, these inhibitors can affect the levels of these neurotransmitters in the body.

Mechanism of Action

Aromatic L-amino acid decarboxylase inhibitors work by binding to the active site of the AADC enzyme, thereby preventing it from catalyzing the decarboxylation of L-amino acids. This inhibition is particularly important in the treatment of Parkinson's disease, where it is used to prevent the peripheral conversion of L-DOPA to dopamine, allowing more L-DOPA to reach the central nervous system.

Clinical Uses

AAAD inhibitors are primarily used in combination with L-DOPA in the treatment of Parkinson's disease. By inhibiting the peripheral conversion of L-DOPA to dopamine, these inhibitors help increase the availability of L-DOPA in the brain, where it can be converted to dopamine and alleviate the symptoms of Parkinson's disease.

Parkinson's Disease

In Parkinson's disease, the loss of dopaminergic neurons in the substantia nigra leads to a deficiency of dopamine in the brain. L-DOPA is a precursor to dopamine and can cross the blood-brain barrier, where it is converted to dopamine. However, if L-DOPA is converted to dopamine in the periphery, it cannot cross the blood-brain barrier, and its effectiveness is reduced. AAAD inhibitors, such as carbidopa and benserazide, are used to prevent this peripheral conversion.

Examples of AAAD Inhibitors

• Carbidopa: Often used in combination with L-DOPA in medications such as Sinemet.
• Benserazide: Used in combination with L-DOPA in medications like Madopar.

Side Effects

The use of AAAD inhibitors can lead to side effects, primarily due to increased levels of L-DOPA in the central nervous system. These side effects may include nausea, dizziness, and dyskinesias. However, the inhibitors themselves are generally well-tolerated.

Related Pages

• Parkinson's disease
• Dopamine
• L-DOPA
• Enzyme inhibitor

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Aromatic L-amino acid decarboxylase inhibitor

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